The present invention relates to powered lighter-than-air aircraft or airships. More specifically, it relates to an aerodynamic fairing for an airship that is selectively deployable and retractable while the craft is aloft.
Powered lighter-than-air aircraft, or airships, have been in existence for more than a century. Typically, such aircraft fall into two major classes: dirigibles and blimps. The major difference between the two is that in the former, the inflatable chambers or balloons are supported in a rigid framework or support structure, while the latter lack a rigid support structure. In both types, the overall shape of the craft typically resembles a cigar, i.e., elongate, with a circular cross-section, a rounded bow or nose, and a stern or tail that is tapered or pointed. This elongate shape provides greater aerodynamic efficiency as compared with, for example, a spherical shape, allowing greater altitude, speed, and endurance (due to improved fuel efficiency) for a given propulsion system. These advantages are achieved, however, at some cost in the efficiency of the distribution of internal and external gas pressures, thereby requiring a more complex pressurization system that would be necessary in a spherical craft. Furthermore, a spherical craft would simplify ground operations, by requiring a smaller landing/lift-off area without the need for a mooring pylon.
It would therefore be advantageous to provide an airship that combines, to the greatest extend possible, the aerodynamic advantages of a conventional, elongate airship with the above-mentioned advantages of a spherical craft. To this end, the prior art has proposed various types of aerodynamic structures and fitting that can be attached to an airship or balloon to improve its aerodynamic efficiency. Nevertheless, it would be a great improvement in airship technology to provide an aerodynamic structure that can be attached to a spherical craft and that can be easily deployed and retracted while the craft is aloft, so that the craft can lift off and land in the manner of a spherical balloon, while greatly increasing aerodynamic efficiency while the craft is in flight.